REDMOND, Wash. -- Microsoft says that Steven Sinofsky, the presidentof its Windows and Windows Live operations, is leaving the company.

Sinofsky's departure comes just weeks after the Redmond, Wash.,software company launched Windows 8, which represented a major overhaulof its ubiquitous computer operating system.

Microsoft (MSFT)said Monday it has promoted company veteran Julie Larson-Green to leadall its Windows software and hardware engineering. Tami Reller will takeover responsibility for the Windows business, while retaining her postsas chief financial officer and chief marketing officer.

The company didn't say why Sinofsky is leaving.

Ina statement, Microsoft CEO Steve Ballmer expressed gratitude forSinofsky's contribution to the company. He indicated the need for thecompany to further integrate its array of offerings, which in additionto Windows includes services such as Bing, Skype and Xbox and a newtablet computer, as it begins what he called "a new era at Microsoft."